Thread: Searching an array

Code:

for (int i=0; i<=n; i++)
{
if (array[i] > 0) break;
}
// i is now the position where the element is greater than 0

Assuming n is the number of elements in array, and that you are using numbers, not chars or another data structure.

If there are two places in the array greater than zero, it breaks on the first one, and you will need more to find other positions that qualify.

Loop through the elements if your array compare them to zero and if that element is than one is the winner.

Here is a 'while' loop version of what you might want to do:

Code:

int Classyclass::winner(const int& array) const
{

        bool flag = false;
	int i = 0;

        while  (i < sizeof(array) && flag==false) 
        {
              if(array[i]!=1)
                   
                   ++i;
                    
               else

	           flag = true;
         }
           

        if(flag)

              return i;    //Return position of winning element

        else
        { 
              cout << "No elements above zero!";
              return -1;   //Return a nonsense negative sentinal value
        }

}

Originally Posted by titleist_03

I'm wanting to search an array. If there is only one value greater than zero then that position in the array is declared the winner. How can I do that?

You all seem to have missed one little word...

ONLY one. Only the first reply seems to have noticed that. But then again, we're just here to get you started. Not do everything for you. Here's an idea:

Code:

int positiveindex = -1;

loop through each element
    if this element greater than zero
        if positiveindex less than zero
            return no winner
        else
            positiveindex equals this spot
if positiveindex less than zero
    return no winner
return positiveindex

Yeah, that pretty much gives it to you. But I'll leave the actual code to you.

Quzah.

Hehe, just to weird people out, here's the fully Boosted version

Code:

#include <iostream>
#include <boost/lambda/lambda.hpp>
#include <boost/range/end.hpp>
using namespace boost::lambda;

int main()
{
	int test[] = { -1, -2, 0, 0, 27, -1 };

	if (std::count_if(test, boost::end(test), _1 > 0) == 1)
	{
		int* winner = std::find_if(test, boost::end(test), _1 > 0);

		std::cout << "We have a winner!"             << std::endl;
		std::cout << "Value is "    << *winner       << std::endl;
		std::cout << "Position is " << winner - test << std::endl;
	}
	else
	{
		std::cout << "No winner. Please play again." << std::endl;
	}
}

boost::end doesn't work in all situations.

Originally Posted by jlou

pseudo-error:

Code:

int positiveindex = -1;

loop through each element
    if this element greater than zero
        if positiveindex greater than or equal to zero
            return no winner
        else
            positiveindex equals this spot
if positiveindex less than zero
    return no winner
return positiveindex

Yeah. Actually the line following my if and else should be swapped:

Code:

    if this element greater than zero
        if positiveindex less than zero
            positiveindex equals this spot
        else
            return no winner
if positiveindex less than zero
    return no winner
return positiveindex

Quzah.

oh yeah